Search results for: reactive oxygen species

Authors: Hameed Rukayat Opeyemi, Pericles Pilidis Pagone Emmanuele, Agbadede Roupa, Allison Isaiah

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Climate change represents one of the single most challenging problems facing the world today. According to the National Oceanic and Administrative Association, Atmospheric temperature rose almost 25% since 1958, Artic sea ice has shrunk 40% since 1959 and global sea levels have risen more than 5.5cm since 1990. Power plants are the major culprits of GHG emission to the atmosphere. Several technologies have been proposed to reduce the amount of GHG emitted to the atmosphere from power plant, one of which is the less researched Advanced zero-emission power plant. The advanced zero emission power plants make use of mixed conductive membrane (MCM) reactor also known as oxygen transfer membrane (OTM) for oxygen transfer. The MCM employs membrane separation process. The membrane separation process was first introduced in 1899 when Walter Hermann Nernst investigated electric current between metals and solutions. He found that when a dense ceramic is heated, the current of oxygen molecules move through it. In the bid to curb the amount of GHG emitted to the atmosphere, the membrane separation process was applied to the field of power engineering in the low carbon cycle known as the Advanced zero emission power plant (AZEP cycle). The AZEP cycle was originally invented by Norsk Hydro, Norway and ABB Alstom power (now known as Demag Delaval Industrial turbomachinery AB), Sweden. The AZEP drew a lot of attention because its ability to capture ~100% CO2 and also boasts of about 30-50% cost reduction compared to other carbon abatement technologies, the penalty in efficiency is also not as much as its counterparts and crowns it with almost zero NOx emissions due to very low nitrogen concentrations in the working fluid. The advanced zero emission power plants differ from a conventional gas turbine in the sense that its combustor is substituted with the mixed conductive membrane (MCM-reactor). The MCM-reactor is made up of the combustor, low-temperature heat exchanger LTHX (referred to by some authors as air preheater the mixed conductive membrane responsible for oxygen transfer and the high-temperature heat exchanger and in some layouts, the bleed gas heat exchanger. Air is taken in by the compressor and compressed to a temperature of about 723 Kelvin and pressure of 2 Mega-Pascals. The membrane area needed for oxygen transfer is reduced by increasing the temperature of 90% of the air using the LTHX; the temperature is also increased to facilitate oxygen transfer through the membrane. The air stream enters the LTHX through the transition duct leading to inlet of the LTHX. The temperature of the air stream is then increased to about 1150 K depending on the design point specification of the plant and the efficiency of the heat exchanging system. The amount of oxygen transported through the membrane is directly proportional to the temperature of air going through the membrane. The AZEP cycle was developed using the Fortran software and economic analysis was conducted using excel and Matlab followed by optimization case study. The Simple bleed gas heat exchange layout (100 % CO2 capture), Bleed gas heat exchanger layout with flue gas turbine (100 % CO2 capture), Pre-expansion reheating layout (Sequential burning layout)–AZEP 85% (85% CO2 capture) and Pre-expansion reheating layout (Sequential burning layout) with flue gas turbine–AZEP 85% (85% CO2 capture). This paper discusses monte carlo risk analysis of four possible layouts of the AZEP cycle.

Keywords: gas turbine, global warming, green house gas, fossil fuel power plants

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Authors: Mohamadreza Hatefi, Malihe Hadadnezhad

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It is well established that jump-landing-related biomechanical deficiencies, such as dynamic knee valgus (DKV), can be improved by using various forms of feedback; However, the effectiveness of these interventions synchronously on athletes' jumping performance remains unknown. Twenty-one recreational athletes with DKV performed countermovement jump (CMJ) and drop vertical jump (DVJ) tasks before and after feedback intervention while the kinematic, force plate and electromyography data of the lower extremity were synchronously captured. The athletes’ jumping performance was calculated by using the reactive strength index-modified (RSIₘₒ𝒹). The athletes at the post-intervention exhibited significantly less hip adduction and more tibial internal rotation during both CMJ and DVJ tasks and maximum knee flexion just during DVJ task. Moreover, athletes exhibited increased time to take-off and consequently decreased RSIₘₒ𝒹 during DVJ task, but no difference was observed in CMJ task. Feedback immediately improved DKV without disturbing the athletes’ jumping height during both tasks, But athletes exhibited increased time to take-off and consequently decreased RSIₘₒ𝒹 only during DVJ task, which suggests that the results may differ according to the nature of jumping task. Nevertheless, the effectiveness of landing-related biomechanical deficiencies improvement on athletes' jumping performance must be investigated in the long-term as a new movement pattern.

Keywords: reactive strength index, feedback, biomechanics, dynamic knee valgus

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Authors: Linmin Zhang

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Entrained-flow gasification technology is considered the most promising gasification technology because of its clean and efficient utilization characteristics. The stable fluidity of slag at high temperatures is the key to affecting the long-period operation of the gasifier. The diversity and differences of coal ash-slag systems make it difficult to meet the requirements for stable slagging in entrained-flow gasifiers. Therefore, coal blending or adding fluxes has been used in industry for a long time to improve the flow behavior of coal ash. As a by-product of the indirect coal liquefaction process, indirect coal liquefaction residue (ICLR) is a kind of industrial solid waste that is usually disposed of by stacking or landfilling. However, this disposal method will not only occupy land resources but also cause serious pollution to soil and water bodies by leachate containing toxic and harmful metals. As a carbon-containing matrix, ICLR is not only a kind of waste but also a kind of energy substance. Utilizing existing industrial gasifiers to blend combustion ICLR can not only transform industrial solid waste into fuel but also save coal resources. Moreover, the ICLR usually contains a unique ash chemical composition different from coal, which will affect the slagging performance of the gasifier. Therefore, exploring the effect of the ash addition in ICLR on the coal ash flow behavior can not only improve the slagging performance and gasification efficiency of entrained-flow gasifier by using the unique ash chemical composition of ICLR but also provide some theoretical support for the large-scale consumption of industrial solid waste. Combining molecular dynamics simulation with Raman spectroscopy experiment, the effect of ICLR addition on slag structure and fluidity was explained, and the relationship between the evolution law of slag short/medium range microstructure and macroscopic flow behavior was discussed. The research found that the high silicon and aluminum content in coal ash led to the formation of complex [SiO₄]⁴- tetrahedron and [AlO₄]⁵- tetrahedron structures at high temperature, and the [SiO₄]⁴- tetrahedron and [AlO₄]⁵- tetrahedron were connected by oxygen atoms to form a multi-membered ring structure with high polymerization degree. Due to the action of the multi-membered ring structure, the internal friction in the slag increased, and the viscosity value was higher on the macro-level. As a network-modified ion, Fe2+ could replace Si4+ and Al3+ in the multi-membered ring structure and combine with O2-, which will destroy the bridge oxygen (BO) structure and transform more complex tri cluster oxygen (TO) and bridge oxygen (BO) into simple non-bridge oxygen (NBO) structure. As a result, a large number of multi-membered rings with high polymerization degrees were depolymerized into low-membered rings with low polymerization degrees. The evolution of oxygen types and ring structures in slag reduced the structure complexity and polymerization degree of coal ash slag, resulting in a decrease in the viscosity of coal ash slag.

Keywords: ash slag, coal gasification, fluidity, industrial solid waste, slag structure

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Authors: Alireza Khaloo, Asghar Gholizadeh-Vayghan

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The present work focuses on the characterization of the physicochemical properties of kaolinitic clays in both raw and calcined (i.e., dehydroxylated) states. The properties investigated included the dehydroxylation temperature, chemical composition and crystalline phases, band types, kaolinite content, vitreous phase, and reactive and unreactive silica and alumina. The thermogravimetric analysis, X-ray diffractometry and infrared spectroscopy results suggest that full dehydroxylation takes place at 639°C, converting kaolinite to reactive metakaolinite (Si₂Al₂O₇). Application of higher temperatures up to 800 °C leads to complete decarbonation of the calcite phase, and the kaolinite converts to mullite at temperatures exceeding 957 °C. Calcination at 639°C was found to cause a 50% increase in the vitreous content of kaolin. Statistically meaningful increases in the reactivity of silica, alumina, calcite and sodium carbonate in kaolin were detected as a result of such thermal treatment. Such increases were found to be 11%, 47%, 240% and 10%, respectively. The ferrite phase, however, showed a 36% decline in reactivity. The proposed approach can be used as an analytical method to determine the viability of the source of kaolinite and proper physical and chemical modifications needed to enhance its suitability for geopolymer production.

Keywords: physicochemical properties, dehydroxylation, kaolinitic clays, kaolinite content, vitreous phase, reactivity

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Authors: Ana Paola Echavarria, Mariuxi Medina, Haydelba D'Armas, Carmita Jaramillo, Diana San Martin

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The use of medicinal plants is one of the oldest and most extended medical therapies that goes back to prehistoric times, and nowadays, they are also used in the preparation of phytopharmaceuticals with options to cure diseases. The test for the determination of fungi was carried out in the Pharmacy Pilot Plant (treatment of the leaves of the plant species) and the Microbiology Laboratory (determination of fungi of the plant species, using growth medium called Sabouraud agar plus the vegetal sample), of the Academic Unit of Chemical Sciences and Health, of the Universidad Tecnica de Machala. Subsequently, colony counting was performed, both macroscopic, which is determined in the growth medium of the seeding, and microscopic, to identify the germinative forms using blue lactophenol. The procedure was repeated in duplicate to replicate the results data. The determination of the total fungal content of the following plant species was evaluated: Cymbopogon citratus (lemon verbena), Melissa officinalis (lemon balm), Taraxacum officinale (dandelion), Artemisia absinthium (absinthe), Piper carpunya (guaviduca), Moringa oleifera (moringa), Coriandrum sativum (coriander), Momordica charantia (achochilla), Borago officinalis (borage), Aloysia citriodora (cedron), Ambrosia artemisifolia (altamisa) and Ageratum conyzoides (mastrante). The results obtained showed that all the samples of the twelve plant species studied developed filamentous fungi, with great variability of them, within the permissible limits and contemplated by the Ecuadorian Institute of Normalization (INEN), being suitable as raw material for its use in the preparation of nutraceuticals and medicinal products or phytodrugs; with the exception of A. conyzoides (mastranto) which is the only species that exceeds the regulation in the average of dilutions.

Keywords: colonies, fungi, medicinal plants, microbiological quality, Sabouraud agar

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Authors: Ahmed Bolaji Alarape, Oluwatobi Damilola Aba

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The growth pattern of Oreochromis niloticus and Sarotherodon galilaeus in Epe Lagoon Lagos State was investigated. One hundred (100) samples of each species were collected from fishermen at the landing site. They were transported to the Fisheries Laboratory of National Institute of Oceanography for identification, sexing morphometric measurement. The results showed that 58.0% and 56.0 % of the O.niloticus and S.galilaeus were female respectively while 42.0% and 44.0% were male respectively. The length-weight relationship of O.niloticus showed a strong regression coefficient (r = 0.944) (p<0.05) for the combined sex, (r =0.901) (p<0.05) for female and (r=0.985) (p<.05) for male with b-value of 2.5, 3.1 and 2.8 respectively. The S.galilaeus also showed a regression coefficient of r=0.970; p<0.05 for the combined sex, r=0.953; p<0.05 for the female and r= 0.979; p<0.05 for the male with b-value of 3.4, 3.1 and 3.6 respectively. O.niloticus showed an isometric growth pattern both in male and female. The condition factor in O.niloticus are 1.93 and 1.95 for male and female respectively while that of S.galilaeus is 1.95 for both sexes. Positive allometric was observed in both species except the male O.niloticus that showed negative allometric growth pattern. From the results of this study, the growth pattern of the two species indicated a good healthy environment.

Keywords: Epe Lagoon, length-weight relationship, Oreochromis niloticus, Sarotherodon galilaeus

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Authors: Yanmei Xiong, Baowen Liao, Kun Xin, Zhongmao Jiang, Hao Guo, Yujun Chen, Mei Li

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Conversion of mangroves to aquaculture ponds represented as one major reason for mangrove loss in Asian countries in the 20th century. Recently the Chinese government has set a goal to increase 48,650 ha (more than the current mangrove area) of mangroves before the year of 2025 and “rehabilitation of aquaculture ponds to mangroves” projects are considered to be the major pathway to increase the mangrove area of China. It remains unclear whether natural colonization is feasible and what are the main influencing factors for mangrove restoration in these projects. In this study, a total of 17 rehabilitation sites in Dongzhai Bay, Hainan, China were surveyed for vegetation, soil and surface elevation five years after the rehabilitation project was initiated. Colonization of non-planted mangrove species was found at all sites and non-planted species dominated over planted species at 14 sites. Mangrove plants could only be found within the elevation range of -20 cm to 65 cm relative to the mean sea level. Soil carbon and nitrogen contents of the top 20 cm were generally low, ranging between 0.2%–1.4% and 0.03%–0.09%, respectively, and at each site, soil carbon and nitrogen were significantly lower at elevations with mangrove plants than lower elevations without mangrove plants. Seven sites located at the upper stream of river estuaries, where soil salinity was relatively lower, and nutrient was relatively higher, was dominated by non-planted Sonneratia caseolaris. Seven sites located at the down-stream of river estuaries or in the inner part of the bay, where soil salinity and nutrient were intermediate, were dominated by non-planted alien Sonneratia apetala. Another three sites located at the outer part of the bay, where soil salinity was higher and nutrient was lower, were dominated by planted species (Rhizophora stylosa, Kandelia obovata, Aegiceras corniculatum and Bruguiera sexangula) with non-planted S. apetala and Avicennia marina also found. The results suggest that natural colonization of mangroves is feasible in pond rehabilitation projects given the rehabilitation of tidal activities and appropriate elevations. Surface elevation is the major determinate for the success of mangrove rehabilitation, and soil salinity and nutrients are important in shaping vegetation structure. The colonization and dominance of alien species (Sonneratia apetala in this case) in some rehabilitation sites poses invasion risks and thus cautions should be taken when introducing alien mangrove species.

Keywords: coastal wetlands, ecological restoration, mangroves, natural colonization, shrimp pond rehabilitation, wetland restoration

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Authors: Wasiu Olaniyi, Ofelia Omitogun

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Hybridization has been of importance in both research and commercial aquaculture due to its benefits such as increased growth rate, sex ratio manipulation, production of sterile species and many other desirable economic traits. In this study, we successfully produced hybrids between crosses of Clariid catfish species of Clarias gariepinus and Heterobranchus bidorsalis for stock improvement. Milt and eggs from parent broodstock of C. gariepinus and H. bidorsalis were collected for both intrageneric and interspecific hybridization, viz: same parent species crosses (♀C. gariepinus ×♂C. gariepinus; ♀H. bidorsalis × ♂H. bidorsalis) and inter-specific crosses (♀H. bidorsalis × ♂C. gariepinus; ♀C. gariepinus × ♂H. bidorsalis). These crosses were made in triplicates whereby the data on latency period, fertility, hatchability, deformity, and survival were recorded. A phenotypic form of distinction was registered in the hybrid ♀C. gariepinus × ♂H. bidorsalis that was smooth-greyed while its reciprocal cross was marpatic. The parent species C. gariepinus had greyed-marpatic color while the H. bidorsalis was yellowish-brown. Fertility data revealed the significant difference (p < 0.05) between the hybrid cross ♀C. gariepinus × ♂H. bidorsalis (88.00 ± 1.00%) compared to its reciprocal ♀H. bidorsalis × ♂C. gariepinus (71.67 ± 10.41%) which further had carried over effects to hatchability. The reciprocal ♀H. bidorsalis × ♂C. gariepinus recorded the highest deformity (11.67 ± 3.06%) that was significantly different (p < 0.05) from the rest of the crosses. Also, an outcome of equal sex ratio in the hybrids compared with the two parent species was shown. Specific growth rate (SGR) data revealed highest significant difference (p < 0.05) in the hybrid ♀C. gariepinus × ♂H. bidorsalis (2.64 ± 0.09%), followed by the cross of ♀C. gariepinus × ♂ C. gariepinus (1.91 ± 0.02%) while there were no significant differences (p > 0.05) between the reciprocal hybrid ♀H. bidorsalis × ♂C. gariepinus (2.20 ± 0.57%) and ♀H. bidorsalis × ♂H. bidorsalis (2.19 ± 0.19%). The SGR analysis proved that the crosses ♀C. gariepinus × ♂C. gariepinus had slow growth performance compared to its hybrid ♀C. gariepinus × ♂H. bidorsalis. Critical evaluation based on survival and specific growth performance showed the superiority of the hybrid ♀C. gariepinus × ♂H. bidorsalis. The least survival in reciprocal hybrid ♀H. bidorsalis × ♂C. gariepinus (27.33%) can be explained by significant deformity (11.67%) recorded due to maternal effects. Hence, the survival of hybrid ♀C. gariepinus × ♂H. bidorsalis was better.

Keywords: aquaculture, hybridization, Clarias gariepinus, Heterobranchus bidorsalis

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Authors: Atilola O. Abidemi-Iromini, Oluayo A. Bello-Olusoji, Immanuel A. Adebayo

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Ecological studies were carried out in Asejire Reservoir (AR) and Lagos Lagoon (LL), Southwest Nigeria from January 2012 to December 2013 to determine the health status of Chrysichthys nigrodigitatus (CN) and Oreochromis niloticus (ON). The fish species samples were collected every month, these were separated into sexes, and growth pattern {length, (cm); weight (g), Isometric index, condition factor} were measured. Heavy metals (lead (Pb), iron (Fe), zinc (Zn), copper (Cu), and chromium (Cr) in ppm concentrations were also determined while bacteria occurrence(s), (load and prevalence) on fish skins, gills and intestine in the two ecological zones were determined. The fish ratio collected is in range with normal aquatic (1: 1+) male: female ratio. Growth assessment determined revealed no significant difference in length and weight in O. niloticus between locations, but a significant difference in weight occurred in C. nigrodigitatus between locations, with a higher weight (196.06 ±0.16 g) from Lagos Lagoon. Highest condition factor (5.25) was recorded in Asejire Reservoir O. niloticus, (ARON); and lowest condition factor (1.64) was observed in Asejire Reservoir C. nigrodigitatus (ARCN); as this indicated a negative allometric value which is normal in Bagridae species because it increases more in Length to weight gain than for the Cichlidae growth status. Normal growth rate (K > 1) occurred between sexes, with the male species having higher K - factors than female species within locations, between locations, between species, and within species, except for female C. nigrodigitatus having higher condition factor (K = 1.75) than male C. nigrodigitatus (K = 1.54) in Asejire Reservoir. The highest isometric value (3.05) was recorded in Asejire Reservoir O. niloticus and lowest in Lagos Lagoon C. nigrodigitatus. Male O. niloticus from Asejire Reservoir had highest isometric value, and O. niloticus species had higher condition factor which ranged between isometric (b ≤ 3) and positive allometric (b > 3), hence, denoted robustness of fish to grow more in weight than in length; while C. nigrodigitatus fish has negative allometric (b < 3) indicating fish add more length than in weight on growth. The status of condition factors and isometric values obtained is species-specific, and environmental influence, food availability or reproduction factor may as well be contributing factors. The concentrations of heavy metals in fish flesh revealed that Zn (6.52 ±0.82) had the highest, while Cr (0.01±0.00) was ranked lowest; for O. niloticus in Asejire Reservoir. In Lagos Lagoon, heavy metals concentration level revealed that O. niloticus flesh had highest in Zn (4.71±0.25) and lowest in Pb (0.01±0.00). Lagos Lagoon C. nigrodigitatus heavy metal concentration level revealed Zn (9.56±0.96) had highest, while Cr (0.06±0.01) had lowest; and Asejire Reservoir C. nigrodigitatus heavy metal level revealed that Zn (8.26 ±0.74) had highest, and Cr (0.08±0.00) had lowest. In all, Zinc (Zn) was top-ranked in level among species.

Keywords: Oreochromis niloticus, growth status, Chrysichthys nigrodigitatus, environments, heavy metals

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Authors: John G. Vongas, Raghid Al Hajj

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We investigated the effects of winning and losing on men’s testosterone and assessed whether androgen reactivity affected their empathic accuracy and their aggression. We also explored whether their power motivation would moderate the relationships between competitive, hormonal, and behavioral outcomes. In Experiment 1, 84 males competed on a task that allegedly gauged their leadership potential and future earnings, after which they interpreted people’s emotional expressions. Results showed that winners were more capable of accurately inferring others’ emotions compared to losers and this ability improved with increasing power. Second, testosterone change mediated the relationship between competitive outcomes and empathic accuracy, with post-competitive testosterone increases relating to more accuracy. In Experiment 2, 72 males again competed after which they were measured on two aggression subtypes: proactive and reactive. Results showed that neither the competitive outcome nor the testosterone change had a significant effect on either types of aggression. However, as power increased, winners aggressed more proactively than losers whereas losers aggressed more reactively than winners. Finally, in both experiments, power moderated the relationship between competitive outcomes and testosterone change. Collectively, these studies add to existing research that explores the psychophysiological effects of competition on individuals’ empathic and aggressive responses.

Keywords: competition, testosterone, power motivation, empathic accuracy, proactive aggression, reactive aggression

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Authors: Mohd Iz'aan Paiz Bin Zamri, Anis Salwa Mohd Khairuddin, Norrima Mokhtar, Rubiyah Yusof

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Effective statistical feature extraction and classification are important in image-based automatic inspection and analysis. An automatic wood species recognition system is designed to perform wood inspection at custom checkpoints to avoid mislabeling of timber which will results to loss of income to the timber industry. The system focuses on analyzing the statistical pores properties of the wood images. This paper proposed a fuzzy-based feature extractor which mimics the experts’ knowledge on wood texture to extract the properties of pores distribution from the wood surface texture. The proposed feature extractor consists of two steps namely pores extraction and fuzzy pores management. The total number of statistical features extracted from each wood image is 38 features. Then, a backpropagation neural network is used to classify the wood species based on the statistical features. A comprehensive set of experiments on a database composed of 5200 macroscopic images from 52 tropical wood species was used to evaluate the performance of the proposed feature extractor. The advantage of the proposed feature extraction technique is that it mimics the experts’ interpretation on wood texture which allows human involvement when analyzing the wood texture. Experimental results show the efficiency of the proposed method.

Keywords: classification, feature extraction, fuzzy, inspection system, image analysis, macroscopic images

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Authors: M. Bučas, A. Skersonas, E. Ivanauskas, J. Lesutienė, N. Nika, G. Srėbalienė, E. Tiškus, J. Gintauskas, A.Šaškov, G. Martin

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Submerged vegetation enhances heterogeneity of sublittoral habitats; therefore, macrophyte stands are essential elements of aquatic ecosystems to maintain a diverse fish fauna. Fish-habitat relations have been extensively studied in streams and coastal waters, but in lakes and estuaries are still underestimated. The aim of this study is to assess temporal (diurnal and seasonal) patterns of fish juvenile assemblages associated with common submerged macrophyte habitats, which have significantly spread during the recent decade in the upper littoral part of the Curonian Lagoon. The assessment was performed by means of an upgraded pop-up net approach resulting in much precise sampling versus other techniques. The optimal number of samples (i.e., pop-up nets) required to cover>80% of the total number of fish species depended on the time of the day in both study sites: at least 7and 9 nets in the evening (18-24 pm) in the Southern and Northern study sites, respectively. In total, 14 fish species were recorded, where perch and roach dominated (respectively 48% and 24%). From multivariate analysis, water salinity and seasonality (temperature or sampling month) were primary factors determining fish assemblage composition. The southern littoral area, less affected by brackish water conditions, hosted a higher number of species (13) than in the Northern site (8). In the latter site, brackish water tolerant species (three-spined and nine-spined sticklebacks, spiny loach, roach, and round goby) were more abundant than in the Southern site. Perch and ruffe dominated in the Southern site. Spiny loach and nine-spined stickleback were more frequent in September, while ruffe, perch, and roach occurred more in July. The diel dynamics of the common species such as perch, roach, and ruffe followed the general pattern, but it was species specific and depended on the study site, habitat, and month. The species composition between macrophyte habitats did not significantly differ; however, it differed from the results obtained in 2005 at both study sites indicating the importance of expanded charophyte stands during the last decade in the littoral zone.

Keywords: diel dynamics, charophytes, pondweeds, herbivorous and benthivorous fishes, littoral, nursery habitat, shelter

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Authors: Ruth Lorivi, Jianzheng Li, John J. Ambuchi, Kaiwen Deng

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Nitrogen removal from wastewater is accomplished by nitrification and denitrification processes. Successful denitrification requires carbon, therefore, if placed after biochemical oxygen demand (BOD) and nitrification process, a carbon source has to be re-introduced into the water. To avoid adding a carbon source, denitrification is usually placed before BOD and nitrification processes. This process however involves recycling the nitrified effluent. In this study wood chips were used as internal carbon source which enabled placement of denitrification after BOD and nitrification process without effluent recycling. To investigate the efficiency of a wood packed aerobic-anaerobic baffled reactor on carbon and nutrients removal from domestic wastewater, a three compartment baffled reactor was presented. Each of the three compartments was packed with 329 g wood chips 1x1cm acting as an internal carbon source for denitrification. The proposed mode of operation was aerobic-anoxic-anaerobic (OAA) with no effluent recycling. The operating temperature, hydraulic retention time (HRT), dissolved oxygen (DO) and pH were 24 ± 2 ℃, 24 h, less than 4 mg/L and 7 ± 1 respectively. The removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH₄⁺-N) and total nitrogen (TN) attained was 99, 87 and 83% respectively. TN removal rate was limited by nitrification as 97% of ammonia converted into nitrate and nitrite was denitrified. These results show that application of wood chips in wastewater treatment processes is an efficient internal carbon source. 

Keywords: aerobic-anaerobic baffled reactor, denitrification, nitrification, wood chip

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Authors: Dewan Hasin Mahtab, Farzana Sadia

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At present, wastewater treatment has become essential to maintain a constant supply of safe water as well as to protect the environment. Due to overpopulation and overconsumption, the water quality from various surface water sources is degrading every day. Being one of the megacities in the world, Dhaka City, is going through rapid industrialization and urbanization. The effluents from these industries and factories are mostly discharged directly into the rivers without any treatment. As such, the quality of water of Buriganga is being afflicted with a noisome problem of pollution. The water of the Buriganga River has become detrimental to humans, animals, and the environment. It has become crucial to conserve the environment so that we can save both ourselves and the environment. The first step towards it should be analyzing the wastewater to decide the further steps of the treatment process. Increased population and increased consumption both contribute to water pollution. Mohammadpur is a developing area of Dhaka City, and Kamrangirchar is one of the largest slum areas in Dhaka City. The total study area is 6.13 sq. Km of Dhaka city with a population of 4,73,310 people. Of them, 86.47% had their own latrine, 47% were directly connected to the drain, 55% had septic tanks, and 70.09% of them cleaned their septic tank once a year. The pH, Dissolved Oxygen, Chemical Oxygen Demand, Biochemical Oxygen Demand, Total Dissolved Solid, Total Suspended and total coliforms of wastewater from two samples of both Mohammadpur and Kamrangirchar was analyzed. The DO level from the water bodies of Kamrangirchar was found very low, making the water bodies inhabitable for aquatic plants and animals. The BOD and COD level was extremely high from samples collected from Mohammadpur. The total coliforms count was found too high during the wet season, making it a potential health concern in the wet season in these two areas.

Keywords: Dhaka, environmental conservation rule, sanitation, wastewater

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Authors: Eya Hentati, Mona Lamine, Jalel Bouzid

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In this study, a laboratory-scale was designed and fabricated to treat single house greywater in the north of Tunisia with a combination of physical and natural treatments systems. The combined system includes a bio-filter composed of LECA® (lightweight expanded clay aggregate) followed by a vertical up-flow constructed wetland planted with Iris pseudacorus and Typha Latifolia. Applied two hydraulic retention times (HRTs) with two different plants types showed that a bio-filter planted with Typha Latifolia has an optimum removal efficiency for degradation of organic matter and transformation of nitrogen and phosphate at HRT of 30 h. The optimum removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids (SS) ranged between 48-65%, between while the nutrients removal was in the range of 70% to 90%. Fecal coliforms dropped by three to four orders of magnitude from their initial concentration, but this steel does not meet current regulations for unlimited irrigation. Hence further improvement procedures are suggested.

Keywords: constructed wetland, greywater treatment, nutriments, organics

Procedia PDF Downloads 163

Authors: Benjawan Saengwichian, Alasdair E. Charles, Philip J. Hyde

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Magnetically controlled growing rods (MCGRs) have been used to stabilise and correct spinal curvature in children to support non-invasive scoliosis adjustment. Although the encapsulated driving components are intended to be isolated from body fluid contact, in vivo corrosion was observed on these components due to sealing mechanism damage. Consequently, a corrosion circuit is created with the body fluids, resulting in malfunction of the lengthening mechanism. Particularly, the chloride ions in blood plasma or cerebrospinal fluid (CSF) may corrode the MCGR alloys, possibly resulting in metal ion release in long-term use. However, there is no data available on the corrosion resistance of spinal implant alloys in CSF. In this study, an in vitro immersion configuration was designed to simulate in vivo corrosion of 440C SS-Ti6Al4V couples. The 440C stainless steel (SS) was heat-treated to investigate the effect of tempering temperature on intergranular corrosion (IGC), while crevice and galvanic corrosion were studied by limiting the clearance of dissimilar couples. Tests were carried out in a neutral artificial cerebrospinal fluid (ACSF) and phosphate-buffered saline (PBS) under aeration and deaeration for 2 months. The composition of the passive films and metal ion release were analysed. The effect of galvanic coupling, pH, dissolved oxygen and anion species on corrosion rates and corrosion mechanisms are discussed based on quantitative and qualitative measurements. The results suggest that ACSF is more aggressive than PBS due to the combination of aggressive chlorides and sulphate anions, while phosphate in PBS acts as an inhibitor to delay corrosion. The presence of Vivianite on the SS surface in PBS lowered the corrosion rate (CR) more than 5 times for aeration and nearly 2 times for deaeration, compared with ACSF. The CR of 440C is dependent on passive film properties varied by tempering temperature and anion species. Although the CR of Ti6Al4V is insignificant, it tends to release more Ti ions in deaerated ACSF than under aeration, about 6 µg/L. It seems the crevice-like design has more effect on macroscopic corrosion than combining the dissimilar couple, whereas IGC is dominantly observed on sensitized microstructure.

Keywords: cerebrospinal fluid, crevice corrosion, intergranular corrosion, magnetically controlled growing rods

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Authors: Zoltán Weltsch, József Hlinka, Eszter Kókai

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The temperature dependence of wettability (wetting angle, Θ (T)) for Ag-based melts on graphite and Al2O3 substrates is compared. Typical alloying effects are found, as the Ag host metal is gradually replaced by various metallic elements. The essence of alloying lies in the change of the electron/atom (e/a) ratio. This ratio is also manifested in the shift of wetting angles on the same substrate. Nevertheless, the effects are partially smeared by other (metallurgical) factors, like the interaction between the oxygen-alloying elements and by the graphite substrate-oxygen interaction. In contrast, such effects are not pronounced in the case of Al2O3 substrates. As a consequence, Θ(T) exhibits an opposite trend in the case of two substrates. Crossovers of the Θ(T) curves were often found. The positions of crossovers depend on the chemical character and concentration of solute atoms. Segregation and epitaxial texture formation after solidification were also observed in certain alloy drops, especially in high concentration range. This phenomenon is not yet explained in every detail.

Keywords: contact angle, graphite, silver, soldering, solid solubility, substrate, temperature dependence, wetting

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Authors: Salah Hadjout, Mohamed Zouidi

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In Algeria, several works carried out in recent years have shown the importance of fusarium head blight in durum wheat. Indeed, this disease is caused by a complex of Fusarium genus pathogens. The research carried out reports that F. culmorum is the main species infecting cereals. These informations motivated our interest in the field evaluation of the behavior of some durum wheat genotypes (parental varieties and lines) with regard to fusarium head blight, mainly caused by four F. culmorum isolates. Our research work focused on following the evolution of symptom development throughout the grain filling, after artificial inoculation of ears by Fusarium isolates in order to establish a first image on the differences in genotype behavior to fusarium haed blight. Field disease assessment criteria are: disease assessment using a grading scale, thousand grain weight measurement and AUDPC. The results obtained revealed that the varieties and lines resulting from crosses had a quite different level of sensitivity to F. culmorum species and no genotype showed complete resistance in our culture conditions. Among the material tested, some lines showed higher resistance than their parents. The results also show a slight behavioral variability also linked to the aggressiveness of the Fusarium species studied in this work. Our results open very important research perspectives on fusarium head blight, in particular the search for toxins produced by Fusarium species.

Keywords: fusarium head blight, durum wheat, Fusarium culmorum, field disease assessment criteria, Algeria

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Authors: Shinta Holdsworth, Jan Axmacher, Darren J. Mann

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Beetles represent the most diverse insect taxon, and they contribute significantly to a wide range of vital ecological functions. Examples include decomposition by bark beetles, nitrogen recycling and dung processing by dung beetles or pest control by predatory ground beetles. Nonetheless, research into the distribution patterns, species richness and functional diversity of beetles particularly from tropical regions remains extremely limited. In our research, we aim to investigate the distribution and diversity patterns of beetles and the roles they play in small tropical island ecosystems in the Kepulauan Seribu Marine National Park and on Java. Our research furthermore provides insights into the effects anthropogenic activities have on the assemblage composition and diversity of beetles on the small islands. We recorded a substantial number of highly abundant small island species, including a substantial number of unique small island species across the study area, highlighting these islands’ potential importance for the regional conservation of genetic resources. The highly varied patterns observed in relation to the use of different trapping types - pitfall traps and flight interception traps (FITs) - underscores the need for complementary trapping strategies that combine multiple methods for beetle community surveys in tropical islands. The significant impacts of human activities have on the small island beetle faunas were also highlighted in our research. More island beetle species encountered in settlement than forest areas shows clear trend of positive links between anthropogenic activities and the overall beetle species richness. However, undisturbed forests harboured a high number of unique species, also in comparison to disturbed forests. Finally, our study suggests that, with regards to different feeding guilds, the diversity of herbivorous beetles on islands is strongly affected by the different levels of forest cover encountered.

Keywords: beetle diversity, forest disturbance, island biogeography, island settlement

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Authors: M. B. Mshelia, J. K. Balogun, J. Auta, N. O. Bankole

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Studies on some aspects of the physico-chemical parameters of Jebba Lake, Niger State, Nigeria was carried out from January to December, 2011. The aim was to investigate some of the physico-chemical parameters relevant to life and health of fish in the water body. Six (6) sampling sites were selected at random which covered Northern (Faku and Awuru), middle (Old Gbajibo and Shankade) and southern zones (New Gbajibo and Jebba dam} of Jebba Lake. Sampling was carried out for the period of 12 Months. The Physico-chemical parameters that were considered were water temperature, pH, dissolved oxygen, electrical conductivity, water transparency, phosphate and nitrate. They were all measured using standard methods. The results showed that water temperature values ranged between 26.06 ± 0.15a in Jebba lake site to 27.34 ± 0.12b in Shankade sampling site, depth varied from 8.08m to 31.64m, water current was between 20.10.62 cm/sec and 26.46 cm/sec, Secchi disc transparency ranged from0.46±0.01 m in New Gbajibo, while the highest mean value was 0.53 ± 0.04 m in Jebba dam., pH varied from 6.49 ± 0.01 and 7.59,5.35±0.03a mg/l in New Gbajibo and 6.75 ± 0.03 mg/l in Faku.The dissolved oxygen varied between 5.35±0.03a mg/l in New Gbajibo and 6.75 ± 0.03 mg/l in Faku.,The mean conductivity value was highest in Faku and Jebba with 128.8 ± 0.32 and 128.8 ± 0.42homs/cm) respectively, Alkalinity ranged 43.00±0.02 to33.30±0.32 mg/l., The nitrate-nitrogen range (2.37 ± 0.08 – 6.40 ± 0.50mg/l)., The mean values of phosphate-phosphorus (PO4-P) recorded varied between 0.18 ± 0.00 mg/l in Faku to 0.47 + 0.10 mg/l in Old Gbajibo.The highest mean value for total dissolved solids was 57.88 ± 0.28 mg/l in Shankade, while the lowest mean value of 39.17 ± 0.42 mg/l was recorded in Faku. Free CO2 ranged from 1.75 mg/l to 2.94 mg/l, Biochemical oxygen demand (BOD) was between 4.25 mg/l and 5.41 mg/l and nitrate-nitrogen concentration was between 2.37 mg/l and 6.40 mg/l. There were significant differences (P < 0.05) between these parameters in relation to stations. Generally, the physico-chemical characteristics of Lake Jebba were within the productive values for aquatic systems, and strongly indicate that the lake is unpolluted.

Keywords: Jebba Lake, water quality, secchi disc, DO meter, sampling sites, physico-chemical parameters

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Authors: Samia Elfekih, Wee Tek Tay, Karl Gordon, Paul De Barro

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Invasive species represent an increasing threat to food biosecurity, causing significant economic losses in agricultural systems. An example is the sweet potato whitefly, Bemisia tabaci, which is a complex of morphologically indistinguishable species causing average annual global damage estimated at US$2.4 billion. The Bemisia complex represents an interesting model for evolutionary studies because of their extensive distribution and potential for invasiveness and population expansion. Within this complex, two species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) have invaded well beyond their home ranges whereas others, such as Indian Ocean (IO) and Australia (AUS), have not. In order to understand why some Bemisia species have become invasive, genome-wide sequence scans were used to estimate population dynamics over time and relate these to climate. The Bayesian Skyline Plot (BSP) method as implemented in BEAST was used to infer the historical effective population size. In order to overcome sampling bias, the populations were combined based on geographical origin. The datasets used for this particular analysis are genome-wide SNPs (single nucleotide polymorphisms) called separately in each of the following groups: Sub-Saharan Africa (Burkina Faso), Europe (Spain, France, Greece and Croatia), USA (Arizona), Mediterranean-Middle East (Israel, Italy), Middle East-Central Asia (Turkmenistan, Iran) and Reunion Island. The non-invasive ‘AUS’ species endemic to Australia was used as an outgroup. The main findings of this study show that the BSP for the Sub-Saharan African MED population is different from that observed in MED populations from the Mediterranean Basin, suggesting evolution under a different set of environmental conditions. For MED, the effective size of the African (Burkina Faso) population showed a rapid expansion ≈250,000-310,000 years ago (YA), preceded by a period of slower growth. The European MED populations (i.e., Spain, France, Croatia, and Greece) showed a single burst of expansion at ≈160,000-200,000 YA. The MEAM1 populations from Israel and Italy and the ones from Iran and Turkmenistan are similar as they both show the earlier expansion at ≈250,000-300,000 YA. The single IO population lacked the latter expansion but had the earlier one. This pattern is shared with the Sub-Saharan African (Burkina Faso) MED, suggesting IO also faced a similar history of environmental change, which seems plausible given their relatively close geographical distributions. In conclusion, populations within the invasive species MED and MEAM1 exhibited signatures of population expansion lacking in non-invasive species (IO and AUS) during the Pleistocene, a geological epoch marked by repeated climatic oscillations with cycles of glacial and interglacial periods. These expansions strongly suggested the potential of some Bemisia species’ genomes to affect their adaptability and invasiveness.

Keywords: whitefly, RADseq, invasive species, SNP, climate change

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Authors: Jaspal Rana, Varinder Singh

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Oxidative stress has been identified as an underlying cause of ischemia-reperfusion (IR) related cognitive dysfunction and brain damage. Therefore, antioxidant based therapies to treat IR injury are being investigated. Allium cepa L. (onion) is used as culinary medicine and is documented to have marked antioxidant effects. Hence, the present study was designed to evaluate the effect of A. cepa outer scale extract (ACE) against IR induced cognition and biochemical deficit in mice. ACE was prepared by maceration with 70% methanol and fractionated into ethylacetate and aqueous fractions. Bilateral common carotid artery occlusion for 10 min, followed by 24 h reperfusion, was used to induce cerebral IR injury. Following IR injury, ACE (100 and 200 mg/kg) was administered orally to animals for 7 days once daily. Behavioral outcomes (memory and sensorimotor functions) were evaluated using Morris water maze and neurological severity score. Cerebral infarct size, brain thiobarbituric acid reactive species, reduced glutathione, and superoxide dismutase activity were also determined. Treatment with ACE significantly ameliorated IR mediated deterioration of memory and sensorimotor functions and rose in brain oxidative stress in animals. The results of the present investigation revealed that ACE improved functional outcomes after cerebral IR injury which may be attributed to its antioxidant properties.

Keywords: allium cepa, cerebral ischemia, memory, sensorimotor

Procedia PDF Downloads 110

Authors: Imdad Ullah Khan, Yongseok Yoon, Kyeung Uk Choi, Kwang Rae Jo, Namyul Kim, Eunbee Lee, Wan Hee Kim, Oh-Kyeong Kweon

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The primary spinal cord injury (SCI) causes mechanical damage to the neurons and blood vessels. It leads to secondary SCI, which activates multiple pathological pathways, which expand neuronal damage at the injury site. It is characterized by vascular disruption, ischemia, excitotoxicity, oxidation, inflammation, and apoptotic cell death. It causes nerve demyelination and disruption of axons, which perpetuate a loss of impulse conduction through the injured spinal cord. It also leads to the production of myelin inhibitory molecules, which with a concomitant formation of an astroglial scar, impede axonal regeneration. The pivotal role regarding the neuronal necrosis is played by oxidation and inflammation. During an early stage of spinal cord injury, there occurs an abundant expression of reactive oxygen species (ROS) due to defective mitochondrial metabolism and abundant migration of phagocytes (macrophages, neutrophils). ROS cause lipid peroxidation of the cell membrane, and cell death. Abundant migration of neutrophils, macrophages, and lymphocytes collectively produce pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1beta (IL-1β), matrix metalloproteinase, superoxide dismutase, and myeloperoxidases which synergize neuronal apoptosis. Therefore, it is crucial to control inflammation and oxidation injury to minimize the nerve cell death during secondary spinal cord injury. Therefore, in response to oxidation and inflammation, heme oxygenase-1 (HO-1) is induced by the resident cells to ameliorate the milieu. In the meanwhile, neurotrophic factors are induced to promote neuroregeneration. However, it seems that anti-stress enzyme (HO-1) and neurotrophic factor (BDNF) do not significantly combat the pathological events during secondary spinal cord injury. Therefore, optimum healing can be induced if anti-inflammatory and neurotrophic factors are administered in a higher amount through an exogenous source. During the first experiment, the inflammation and neuroregeneration were selectively targeted. HO-1 expressing MSCs (HO-1 MSCs) and BDNF expressing MSCs (BDNF MSC) were co-transplanted in one group (combination group) of dogs with subacute spinal cord injury to selectively control the expression of inflammatory cytokines by HO-1 and induce neuroregeneration by BDNF. We compared the combination group with the HO-1 MSCs group, BDNF MSCs group, and GFP MSCs group. We found that the combination group showed significant improvement in functional recovery. It showed increased expression of neural markers and growth-associated proteins (GAP-43) than in other groups, which depicts enhanced neuroregeneration/neural sparing due to reduced expression of pro-inflammatory cytokines such as TNF-alpha, IL-6 and COX-2; and increased expression of anti-inflammatory markers such as IL-10 and HO-1. Histopathological study revealed reduced intra-parenchymal fibrosis in the injured spinal cord segment in the combination group than in other groups. Thus it was concluded that selectively targeting the inflammation and neuronal growth with the combined use of HO-1 MSCs and BDNF MSCs more favorably promote healing of the SCI. HO-1 MSCs play a role in controlling the inflammation, which favors the BDNF induced neuroregeneration at the injured spinal cord segment of dogs.

Keywords: HO-1 MSCs, BDNF MSCs, neuroregeneration, inflammation, anti-inflammation, spinal cord injury, dogs

Procedia PDF Downloads 115

Authors: Endrick Barnacin, Jean-Luc Henry, Jack Molinié, Jimmy Nagau, Hélène Delatte, Gérard Lebreton

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Palynology is a field of interest for many disciplines. It has multiple applications such as chronological dating, climatology, allergy treatment, and even honey characterization. Unfortunately, the analysis of a pollen slide is a complicated and time-consuming task that requires the intervention of experts in the field, which is becoming increasingly rare due to economic and social conditions. So, the automation of this task is a necessity. Pollen slides analysis is mainly a visual process as it is carried out with the naked eye. That is the reason why a primary method to automate palynology is the use of digital image processing. This method presents the lowest cost and has relatively good accuracy in pollen retrieval. In this work, we propose a system combining recognition and grouping of pollen. It consists of using a Logistic Model Tree to classify pollen already known by the proposed system while detecting any unknown species. Then, the unknown pollen species are divided using a cluster-based approach. Success rates for the recognition of known species have been achieved, and automated clustering seems to be a promising approach.

Keywords: pollen recognition, logistic model tree, expectation-maximization, local binary pattern

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Authors: Abu Salim Mustafa

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Brucellosis is a zoonotic disease endemic in Kuwait. Human brucellosis can be caused by several Brucella species with Brucella melitensis causing the most severe and Brucella abortus the least severe disease. Furthermore, relapses are common after successful chemotherapy of patients. The classical biochemical methods of culture and serology for identification of Brucellae provide information about the species and serotypes only. However, to differentiate between relapse and reinfection/epidemiological investigations, the identification of genotypes using molecular methods is essential. In this study, four molecular methods [16S rRNA gene sequencing, real-time PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus variable-number tandem-repeat analysis (MLVA)-16] were evaluated for the identification and typing of 75 strains of Brucella isolated in Kuwait. The 16S rRNA gene sequencing suggested that all the strains were B. melitensis and real-time PCR confirmed their species identity as B. melitensis. The ERIC-PCR band profiles produced a dendrogram of 75 branches suggesting each strain to be of a unique type. The cluster classification, based on ~ 80% similarity, divided all the ERIC genotypes into two clusters, A and B. Cluster A consisted of 9 ERIC genotypes (A1-A9) corresponding to 9 individual strains. Cluster B comprised of 13 ERIC genotypes (B1-B13) with B5 forming the largest cluster of 51 strains. MLVA-16 identified all isolates as B. melitensis and divided them into 71 MLVA-types. The cluster analysis of MLVA-16-types suggested that most of the strains in Kuwait originated from the East Mediterranean Region, a few from the African group and one new genotype closely matched with the West Mediterranean region. In conclusion, this work demonstrates that B. melitensis, the most pathogenic species of Brucella, is prevalent in Kuwait. Furthermore, MLVA-16 is the best molecular method, which can identify the Brucella species and genotypes as well as determine their origin in the global context. Supported by Kuwait University Research Sector grants MI04/15 and SRUL02/13.

Keywords: Brucella, ERIC-PCR, MLVA-16, RT-PCR, 16S rRNA gene sequencing

Procedia PDF Downloads 387

Authors: Joserra Díez, Ainhoa Meñika, Iñaki Sanz-Azkue, Arritokieta Ortuzar

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Biodiversity provides humans with a great range of ecosystemic services; it is therefore an indispensable resource and a legacy to coming generations. However, in the last decades, the increasing exploitation of the Planet has caused a great loss of biodiversity and its acquaintance has decreased remarkably; especially in urbanized areas, due to the decreasing attachment of humans to nature. Yet, the Primary Education curriculum primes the identification of flora and fauna to guarantee the knowledge of children on their surroundings, so that they care for the environment as well as for themselves. In order to produce effective didactic material that meets the needs of both teachers and pupils, it is fundamental to diagnose the current situation. In the present work, the knowledge on biodiversity of 3^rd cycle Primary Education students in Biscay (n=98) and its relation to the size of the town/city of their school is discussed. Two tests have been used with such aim: one for tree identification and the other one so that the students enumerated the species of trees and animals they knew. Results reveal that knowledge of students on tree identification is scarce regardless the size of the city/town and of their school. On the other hand, animal species are better known than tree species.

Keywords: biodiversity, population, tree identification, animal identification

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Authors: Ayyavu Brama Dhayala Selvam

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Herbal medicines are gaining importance due to holistic nature and lesser side effects. Cycas beddomei Dyer is one of the highly exploited medicinal plants in India. Due to over-exploitation of male and female cones, young leaves and starch-bearing pithy stems for edible, medicinal and socio-cultural practices by the locals, tribals and traders, the plant population has drastically declined in its natural habitats. Cycas beddomei is an endemic to India. The current IUCN status of this plant species in the wild is endangered. Perhaps, it is the only species of Cycas enlisted in Appendix I of CITES (Convention on International Trade in Endangered Species of wild fauna and flora). Endorsing the CITES decisions, the Government of India has placed C. beddomei in the “Negative List of Exports” during 1998. Though this plant has been banned legally, but illegally, it is highly exploited by different means. Therefore, conservation of this species is an urgent need of the hour. The present paper highlights unique morphological and anatomical characters of C. beddomei, along with its present status, major threats and conservation measures. Cycas beddomei can easily be identified by some of the distinguishing morphological and anatomical characters, viz., 2–4 mm wide leaflets with revolute margins; the apices of microsporophylls from the middle to apex of the pollen cones turn downwards on maturity; mucilage canal cells are seen in the midrib region of the leaflets; stomatal frequency is about 18 numbers at 250x; pollen grains are monocolpate and their diameter ranging from 22.5 to 30 µm.

Keywords: CITES, Cycas beddomei, endangered, endemic

Procedia PDF Downloads 291

Authors: N. K. A. M. Galvão, A. Godoy Jr., A. L. J. Pereira, G. V. Martins, R. S. Pessoa, H. S. Maciel, M. A. Fraga

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Silicon carbide (SiC) is a wide band-gap semiconductor material with very attractive properties, such as high breakdown voltage, chemical inertness, and high thermal and electrical stability, which makes it a promising candidate for several applications, including microelectromechanical systems (MEMS) and electronic devices. In MEMS manufacturing, the etching process is an important step. It has been proved that wet etching of SiC is not feasible due to its high bond strength and high chemical inertness. In view of this difficulty, the plasma etching technique has been applied with paramount success. However, in most of these studies, only the determination of the etching rate and/or morphological characterization of SiC, as well as the analysis of the reactive ions present in the plasma, are lowly explored. There is a lack of results in the literature on the chemical and structural properties of SiC after the etching process [4]. In this work, we investigated the etching process of sputtered amorphous SiC thin films on Si substrates in a reactive ion etching (RIE) system using sulfur hexafluoride (SF6) gas under different RF power. The results of the chemical and structural analyses of the etched films revealed that, for all conditions, a SiC crystallization occurred, in addition to fluoride contamination. In conclusion, we observed that SiC crystallization is a side effect promoted by structural, morphological and chemical changes caused by RIE SF6 etching process.

Keywords: plasma etching, plasma deposition, Silicon Carbide, microelectromechanical systems

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Authors: Irianes C. Gozali, Betty J.L. Laglbauer, Muhammad G. Salim, Sila K. Sari, Fahmi Fahmi, Selvia Oktaviyani

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Muncar, located off the eastern coast of Java, is an important fishing port for small-scale fleets which land mobulid rays as retained bycatch, primarily in drift gillnets. Due to overlap with fishing grounds in the Bali Strait, three devil ray species are landed in Muncar, the spinetail devil ray Mobula mobular, the bentfin devil ray Mobula thurstoni, and the Chilean devil ray Mobula tarapacana, which are all listed as Endangered by the International Union for the Conservation of Nature. However, despite the importance of life-history data to better manage stocks, such information is still rare or unavailable for Indonesian mobulid ray populations. Using morphometric data, reproductive assessments, and samples collected from dead specimens at fish markets from 2015-2019, we provide information on the maturity stage, reproductive periodicity, gestation, and size at parturition. A majority of immature individuals of all three devil ray species were recorded (<10% individuals in Mobula mobular to <30% individuals in Mobula thurstoni). Pregnant females of two species, Mobula mobular and Mobula thurstoni were recorded containing embryos of various developmental stages (each with a single embryo in the left functional uterus), while for Mobula tarapacana, no fetuses were found. The largest embryo recorded in M. mobular was within the range of that previously reported for neonates of the species in Indonesia (957 cm, for a 920-994 range), and represents a near-term embryo reflecting size at parturition. Low reproductive output was confirmed for the study-species. Based on this study, we infer that the Bali Straight is likely an important location for devil ray reproduction, which raises concern for the sustainability of mobulid ray populations in the face of bycatch in drift gillnets. Potential management approaches to tackle this issue are discussed.

Keywords: devil ray, mobulid, reproduction, Indonesia

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Authors: Malinwo Estone Ayikpa

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Electric power systems are likely to operate with minimum losses and voltage meeting international standards. This is made possible generally by control actions provide by automatic voltage regulators, capacitors and transformers with on-load tap changer (OLTC). With the development of photovoltaic (PV) systems technology, their integration on distribution networks has increased over the last years to the extent of replacing the above mentioned techniques. The conventional analysis and simulation tools used for electrical networks are no longer able to take into account control actions necessary for studying distributed PV generation impact. This paper presents an unbalanced optimal power flow (OPF) model that minimizes losses with association of active power generation and reactive power control of single-phase and three-phase PV systems. Reactive power can be generated or absorbed using the available capacity and the adjustable power factor of the inverter. The unbalance OPF is formulated by current balance equations and solved by primal-dual interior point method. Several simulation cases have been carried out varying the size and location of PV systems and the results show a detailed view of the impact of PV distributed generation on distribution systems.

Keywords: distribution system, loss, photovoltaic generation, primal-dual interior point method

Procedia PDF Downloads 329